A 71-year-old man presents with right testicular pain, non-radiating, of three months' duration, with an increase in testicular diameter and consistency in the last month. He presents with constitutional syndrome, with a weight loss of 3 kg in the last month. Peak fever up to 39ºC, profuse sweating, non-clinical micturition, no haematuria. Of note was COPD with treatment with inhalers and chronic home oxygen.
On physical examination, the patient was affected, with mucocutaneous pallor, crackles on pulmonary auscultation, oedema in the lower limbs, no adenopathies, haematomas in both upper limbs. The genital examination of the right hemiscrotal showed oedema of the lining, increased consistency of the epididymis and teste, with disappearance of the epididymal-testicular groove, with no signs of fluctuation or abcessation. Digital rectal examination of the prostate adenomatous prostate, grade II-III/IV.
Analyses: haemoglobin 8.1 g/dl (previous 13.5 g/dl), platelets 51000, 9100 leukocytes. Coagulation fibrinogen elevation 1500 (limits of normality below 400). Elevated lactate dehydrogenase (LDH), BHCG, CEA, AFP, normal renal, hepatic and pancreatic function. Chest X-ray, minimal vascular congestion, normal abdominal X-ray.
Renal and bladder ultrasound without alterations, prostate measuring 4.5 x 4 x 4.1 cm. Testicular ultrasound, left testicle normal, right testicle with three heterogeneous areas with decreased echogenicity, no calcifications affecting the upper pole, lower pole and epididymis, no hydrocele.

With the diagnostic suspicion of testicular abscess versus testicular tuberculosis, brucellosis or testicular tumour, we performed a radical orchiectomy via the inguinal route.
The pathological anatomy reports, macroscopically, a testicular tumour measuring 8 x 6 x 4 cm, with a 5.5 cm lobulated whitish mass in section, which infiltrates the albuginea and epididymis but does not go beyond the external layer or the hilar border. Microscopically, the testicle is affected by diffuse large B-cell lymphoma, with a high proliferation rate (minb1 > 80%), and CD 20+ markers. Stage 1E-B.

With the diagnosis of primary testicular lymphoma, we requested a full body CT scan for staging, showing homogeneous splenomegaly, isolated retroperitoneal lymphadenopathy of less than 1 cm, as notable findings.
Post-surgical evolution of the patient showed profuse sweating, fever in peaks, asthenia and oedema of the lower limbs. Analyses persist, anaemia 8.9 g/dl haemoglobin, platelets 37000, and normal leukocyte and lymphocyte formula.
With the diagnosis of B symptoms in a patient with primary testicular lymphoma, we performed a bone marrow biopsy, obtaining a cylinder measuring 3 x 0.3 cm, in which there is hypercellular bone marrow with regenerative and dysplastic changes, at the expense of the granulocytic series. There is marked interstitial plasmacytosis, infiltration by lymphoblastic cells.

As there was no evidence of bone marrow infiltration, we performed a blood smear to justify the cause of the anaemia and thrombocytopenia. Platelet aggregation was observed and a direct Coombs' test was performed, which was weakly positive for immunoglobulin G, the cause of the aggregation.
On admission to hospital the patient began with dysphonia and dysphagia and fibroscopy was performed, showing a polypoid lesion in the pyriform sinus. The cervical CT scan was normal. During admission the patient was prescribed Rituximab and the following day the first cycle of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), presenting intense improvement of the B symptoms, with disappearance of the fever. Chemotherapy treatment was started with 6 cycles of R-CHOP. Coadjuvant genital radiotherapy and cerebral chemoprophylaxis were administered. At 12 months the patient was free of disease.
